Gas fired hot air furnace



Jan. 1, 1935. s. H. HOBSON GAS FIRED HOT AIR FURNACE Original Filed Aug.9, 1929 I5 Sheets-Sheet 1 1, s. H. HOBSON, 1,936,675

GAs'FIRED HOT AIR FURNACE Original Filed Aug. 9, 1929 3 Sheets-Sheet 2 31935- s. H. HOBSON 1,986,675

GAS FIRED HOT AIR FURNACE Original Filed Aug. 9, 1929 3 Sheets-Sheet 5Fr M4. 6 T: a

" hot air furnace.

6 years, but were generally used only in those that the corrugationsafford longitudinal chan- 0 This form of radiator sections, in additionto Patented Jan. 1, 1935 UNITED STATES PATENT oFFica GAS FIRED HOT AIRFURNACE Stanley H. Hobson, Rockford, 111., assignor to Geo.

D. Roper Corporation, Rockford, 11]., a corporation of IllinoisApplication August 9, 1929, Serial No. 384,553

Renewed May 16, 1934 40 Claims. (Cl. 126-116) This invention relates toan improved gas fired flow, in straight paths from the lower ends to theupper ends of the columns. In other words,

the special formation of the surface to obtain. increased area is notmade at the sacrifice of unobstructed air passages. As evidence of thesoundness of this principle of operation, itis to be noted that theefliciency of a furnace utilizing radiator sections of this descriptionwas found to be 72%, as compared with an efiiciency of or less securedwith other gas fired furnaces with which I am familiar.

Among other features of the furnace of my invention which are alsoresponsible for its aidcient operation, may be mentioned theprovision oflarge inlet openings for the columns of Furnaces of the kind referred tohave been made in various designs for quite a number of localities wherenatural gas is available at low cost; their efliciency was admittedlyvery low and it was out of the question for a manufacturer of suchfurnaces to attempt to compete with manufacturers of other kinds ofheating equipment on the basis of economy in operation in localitieswhere only artificial gas is available. It is, therefore, the principalobject of my invention to provide a-gas fired furnace of such improveddesign and construction that the products of combustion are sothoroughly and completely stratified and so' much area is presented totake up the heat therefrom and transfer it to the air, that the furnaceoperates economically enough, at least as compared with oil burners, tomake the same practical and suitable for operation with artificial gas,there being the advantages with this kind .of furnace over oil burnersthat one does not have to have a storage tank that has to be refilledregularly, that there is practically no odor, vapors, or soot incidentto the operation thereof, and no objectionable noise. More specificallystated, I provide a plurality of radiator sections extending from alowercombustion manifold to an upper flue manifold, each of which has thecolumns thereof of flattened section so as to cause the products ofcombustion in passing therethrough to be spread out into as thin streamsas possible, and thus make for the most efliclent heat exchange throughthe walls of the radiator sections with the air passing over the outsideof the latter. In addition to this feature of spreading out the productsof combustion into thin streams, which partly accounts for the goodefficiency of operationof the furnace, I have found that bylongitudinally corrugating the walls of the columns of the radiatorsections, I secure still better efiiciency, because in that way thestreams are further broken up into a multiplicity of separate streams,each of which flows through a separate, substantially tubular channel,so that the air to be heated has access thereto from all sides toabstract as much heat therefrom as possible.

floating at the burner by allowing easy take-off of the productsofcombustion, the outlets for said columns leading into the fluemanifold being of smaller size so as not to permit of too rapid flow ofthe products of combustion through the columns, such as would beinconsistent with efiicient heat transfer to the air to be heated. It isalso important to mention the baflles mounted in the outlet openingshaving different sized openings therein for the different radiatorsections, with the idea of preventing faster flow of products throughone section than through another, because of heavier draft effect at onepoint of the flue manifold than at'another, it being found that thedraft is heaviest at the middle and lighter at the ends, so that thebailie openings should be larger for the end sections than for themiddle sections to equalize the draft effect.

I have embodied various other advantageous features of construction inthe furnace that make for economical production, ease in assembling andinstalling, and simplicity of control and regulation of the' operation,as well as general neatness in appearance, among which may be mentioned,in addition to the-sectional construction of the entire radiator unit,mentioned above, the provision of rigid front supporting legs for theradiator unit, in combination with "a movable rear supporting leg, therocking of which permits the expansion and contraction of the unit inthe operation of the furnace; the provision of adjusting screws on thefeet of the supporting legs by means of which the radiator unit can beaccurately leveled on an uneven basement floor for giving the desiredincreased surface area for eflicient operation of the burner; theprovision of contact by the air to be heated, is of advantage in wall ofwhich is formed mainly by a door, the closnels on the outside of thecolumns to conduct ing of which covers up all of the valves and pip-'streams of air, with minimum obstruction to ing to simulate a cabinetfor neatness in appearthe radiator sections that serve to avoid dangerof a double-walled front for the fum'ace the outer ply pipe through afloat-controlled valve which serves to maintain a predetermined level ofwater in the pan at all times.

The invention is illustrated in the ing drawings, wherein- Figure 1 is alongitudinal, vertical section through my improved furnace showingcertain accompany 'portions of the radiator unit in side elevation;

Figs. 2 .and 3 are transverse sections taken on the line 2-2 and 3--3 ofFig. 1;

Fig. 4 is a longitudinal, horizontal section taken on the broken line4-4 of Fig. 1;

Fig. 5 is a view of one set of the outlet openings showing how all butthe front one are restricted more or less by the use of baflles havingdifferent sized openings for the different sections;

Fig. 6 is a longitudinal section through one of the bafiies shown inFig. 5, being taken on the line 6-6 thereof, as indicated, and

Fig. 7 is a fragmentary. sectional detail of the front end of thehumidifier pan taken on the line 7-7 of Fig. 2, showing how the waterlevel therein is maintained by a float-controlled water supply valve.

The same reference numerals are applied to corresponding partsthroughout the views.

Gas fired furnaces have been built utilizing circular and other shapedburners, but I prefer to employ a long narrow burner 10 extendingsubstantially-the full length of a narrow, elongated combustion manifold11 of a. radiator unit 12 and having its pipe 13 for the delivery of itsmixture of fuel and air extending from the middle thereof to the gascock 14, at which point the usual shutter plate 15 is provided to permitregulating the inflow of air in the usual way. A pilot burner 16 isprovided at the front end of the main burner and has connection througha. valve 17 with the gas supply pipe 18 at a point in front of theshut-off valve 19. Thus, the pilot burner is arranged to remain lit solong asthe valve 19 is left open. Another valve 20, under the'control ofthermostaticallyecontrolled mechanism 21, shuts off the gas for the mainburner according to the setting of a thermostat placed in' one of therooms of the house being heated. The pilot burner 16 usually has athermostat associated therewith heated by the flame thereof andelectrically connected with the mechanism 21 and arranged in the eventthe flame is extinguished to close the valve independently of thethermostat previously referred to, whereby to avoid the condition ofhaving the gas delivered to the main burner without a pilot light toignite the same. This sort of control is so well known, there is thoughtto be no need for further explanation.

The radiator unit 12 is made up of a plurality of individual radiatorsections 22 each having a pair of laterally spaced, substantiallyparallel hollow columns 23 I extending from both sides of the top of alower housing portion 24 up to the opposite sides of the top of an upperhousing portion 25, all cast in one piece. housing portions 24 of theradiator sections are flanged, as indicated at 26, and are arranged tofit snugly in abutting relation to form the com- The lower bustionmanifold 11, and the upper housing portions 25 are similarly flanged, asshown at 27, to fit snugly in abutting relation to form the fluemanifold 28. Lugs 29 on the lower housings 24 permit the bolting of theabutting sections together at their lower ends by short bolts 30.Through bolts 31 reach the full length of the outside of the combustionmanifold 11 and serve not only to further draw the sections together,but also fasten the same to a front casting 32 and a back plate 33. Thelatter serves simply to close the rear end of ,the combustion manifold,but the former provides a compartment for the pilot light 16 and cock 14at the outer end of the burner. 10. A cover plate 32' is provided forthe casting 32 and provides a mounting for a door 34 having a window 35therein affording access to the burner for lighting the same when thedoor is swung open, and a view of the flame to determine the results ofadjustment of the cook 14 or shutter plate 15 when the furnace is beingregulated. The plate 32' also has an air inlet opening 36 belowthe door34 so that there is adequate supply of air to the burner for goodcombustion.

A pair of laterally spaced legs 37 reach downwardly from the casting 32to rigidly support the front end of the radiator unit. The rear endthereof is movably supported by another leg 38 through the medium oftrunnions 39 which have knife edges 40 seating in openings in lugs 41provided on the upper end of the leg 38. Screws 42 thread throughlaterally spaced feet provided on the legs 37 and 38, and are arrangedto be adjusted to level theradiator unit 12 as a whole, regardless ofunevenness of the floor on which the furnace is set, with the object ofgetting the burner 10 absolutely horizontal for most eflicientcombustion, it being found that the flame tends and forth as theradiator unit expands and contracts in the operation of the furnace. Inpassing, it will be noted that another set of through bolts 43 areprovided extending the full length of the flue manifold 28 and serve notonly to draw the radiator sections together, but, also fasten a frontplate 44 and a flue outlet casting 45 onto the opposite ends of saidmanifold, the former serving merely to close the front end of themanifold, and the latter being arranged, of course, to have a pipeattached thereto for communication with a chimney.

In operation, considering 'only the radiator unit thus far described, itis evidentv that the products of combustion are conducted from thecombustion manifold 11 through the columns 23 of the plurality ofradiator sections into the flue manifold 28, and thence to the chimneythrough the flue outlet 45. Now, assuming that cold, fresh air to beheated is being delivered below the radiator unit so as to flow upwardlytherethrough to the hot air ducts leading to the rooms to be heated, itis evident that the transfer of the heat from the products of combustionto the air is efficient only in proportion to the radiation areaafforded, that is, area of metal contacted by both the products ofcombustion and the air to be heated. A large amount of radiation area issecured by making the columns 23 of flattened cross-section so that theproducts flowing therethrough are spread out in thin streams from whichthe heat is dissipated from both sides through the opposed walls, theproducts being in heat transferring contact with these walls on v theinside, and the air being in heat transferring contact with the outsidethereof. Additional radiation area is-built into small space by providing the flattened columns with longitudinal corrugations 46, thecolumns shown having radiation area equivalent to columns from 30% tobroader, as should be evident from a consideration of Fig. 4, wherethese corrugations are shown to best advantage. The corrugationing issuch that the troughs thereof in the opposed walls are in line with oneanother, as shown, so as'to form substantially tubular channels orpassages 47 through which the products are caused to flow. In otherwords, the thin streams of products previously referred to are eachsplit up into a multiplicity of separate streams, from which the heat isreadily dissipated to the surrounding'air through the walls encasing thesame from practically- .all sides. There is a very eflicient scrubbingaction of the air on the columns in the passage of the air along thelongitudinal channels on the outside thereof. The air is conducted alongthese channels, with minimum obstruction to flow, in straight paths fromthe lower ends to the upper ends of the columns. The special formationof the columns to obtain increased surface area is not, therefore, madeat the sacrifice to unobstructed air passages. Where protruding knobs orradiating projections were provided, for example, there was too muchobstruction to the flow of the air created thereby, and as a result, theair never had more than superficial contact therewith and the efficiencyof operation was correspondingly low. The' channels 47 are, of course,not entirely separated, but are in communication with one another to theextent indicated in Fig. 4, but still theresult described is produced.to about the same extent as if the combustion manifold were connectedwith the flue manifold by as many parallel pipes as there are channels47. The fact thatthe columns 23 are cast with the channels 47 incommunication with one. another, makes it possible to clean out thecolumns with a flexible handled brush entered from the combustionmanifold 11 and worked upwardly therefrom, the burner 10being'preferably removed to give enough room. Still further increase inthe efliiciency in the transfer of heat from the products of combustionto theair is secured by the additional radiation area afforded bylongitudinal flanges 48 on the inner edges of the columns and similarflanges 49 on the outer edges thereof.

The efficiency of the furnace is also propor:

tionately high if the heat losses by radiation directly from the furnaceitself are kept down to a minimum. In other words, the cooler theoutside walls of the casing 50 are, the higher the efiiciency of thefurnace is bound to be, because it is evidence that the heat in theradiator unit 12 is not being dissipated through the casing. Thedisposition of the radiator sections 22 edgewise with respect to theside walls of the casing exposes very little radiation area toward saidwalls, which obviously means a proportionately diminished dissipation ofheat from the radiator unit 12 through the walls of the casing. In orderfurther to cut down the heat dissipation, I provide the side walls 51with inner walls 52 spaced therefrom so as to provide insulating airchambers 53. The back wall 54 is also provided with an inner wall 55 soas to form an insulating air chamber 56 for'a similar purpose. The frontof the casing is made so as to form still another insulating air chamber57. An inner wall 58 to which the front casting S2 'of the radiator unit"12 and its cover plate 32' are suitably secured, is

set in in the front end of the casing 50 sufllcient- 1y to provide thechamber 5'? in front of it. wherein the valves 17, 19 and 20 and thethermostatic control mechanism 21 are received, and a door 59constitutes the outer front wall for said chamber. The door 59 reachessubstantially the full height of the casing and is hingedat one sidethereof, as shown at 60, and provided at the other side thereof with aknob 61, the turning of which is arranged to lock or unlock the door-bythe operation of latch rods 62. -When the door is opened, access may behad to the entire front of the furnace and all of the control valves arewithin easy reach. When the door is closed, the

furnace presents the neatness in appearance of as previously described.Thus, air for the burner is taken in by a direct path from in front ofthe casing. Cold, fresh air to be heated is delivered to the bottom ofthe casing through ducts 64 communicating with opposite sides of thecasing, as shown in Fig. 4, and a hood 65 covers the top of the casingand has the hotair ducts represented in dotted lines at 66 in Fig.1radiating therefrom in different directions. Since all sides of theeasing are insulated and there is'minimum radiation of heat from theradiator unit to the walls of the casing, by reason of the arrangementof the radiator sections, as above described, it should be evidentthat'the-air admitted to the bottom of the casing through the ducts 64will be heated evenly in its passage upwardly over the large radiationarea afforded on the radiator unit 12 and distributed to the variousparts of the building throughthe ducts 66. Theair is not s'ubje'ctedatany time to intensive heating, such as would tend to drive out itsnatural moisture content, but in the event the air is too dry, it isarranged to pick up moisture from the water in a humidifier pan 67 whichis entered through an opening 68 in the inner front wall 58 and hasoutwardly directed flanges 69 on opposite sides thereof received inregistering notches 70 provided in the flanges 43 for the support of thepan between the two rows of columns 23 directly over the combustionchamber 11. A plate 71-, forming the front wall of the pan 67. isarranged to be bolted to the inner front wall 58 of the casing, asindicated at '72. A water supply pipe 73 has an elbow connection 74 witha. valve 75 provided on the inside of the pan 67, and a float 76controls the opening and closing of the latter so as to maintain acertain level of water in the pan at all times. Thus, the humidifyingofthe air'is always automatically assured and the operator never has tobother filling the pan. In passing, it will be observed that a plate 7'7is bolted over a hand hole 78 in the wall 58 directly in line with thecover plate 44 provided, as

described before, at the front end of the flue manifold 28 of theradiator unit 12. -When the columns are being cleaned out as previouslymento permit the removal of cleats 79 and baflies '80 so that thecleaning brush can be worked up all the way through the columns of theradiator sections. The purpose of the battles will now be described.

- A very important factor in the eificiency of the furnace is the matterof making all of the radiator sections 22 function alike; the flow ofthe products of combustion through all of the radiator sections has tobe at substantially the same rate for maximum eiiiciency. The difficultyin securing such uniform operation of said radiator sections lies in thefact. that the draft efiect is not uniform at all points along the fluemanifold 28; it is found that the heaviest draft is 'at the middle andthe draft is lighter at the ends. I have, therefore, provided the'baflies 80 in the outlets 81 of the columns 23, having different sizedopenings 81' provided therein for the different radiator sections toequalize the draft effect for all of the sections and thus tend to makethe flowof the products of combustion through all of the said sectionsuniform. Fig. shows how the openings 81' in the various bafiies 80for'the different sections compare with one another in size. The outletsfor the front section are left uncovered, the full area of one of theseopenings 81 being represented merely by an outline at the left hand endof Fig. 5. I prefer to make the baflies 80 in the form of small flatplates cast to the form shown in longitudinal section in Fig. 6providing below the opening 81' three distinct transverse ribs 82separated by thin webs 83 such that one, two or all three of the ribscan be knocked out with a chisel to enlarge the opening 81' to theextent desired. By reference to Fig. 5, it will be observed that certainof the baflies have some of the ribs 82 knocked out for the purposestated.

Below the ribs 82 is a panel 84 also separated from the ribs and fromthe rest of the body of the baflle by thin webs 83. Thus, it is possibleto knock out this panel along with the ribs if a large opening isdesired in the baflie. The baflie shown at the right hand end of Fig. 5has all of the ribs 82 and panel 84 knocked out for that purpose. It is,therefore, evident that in the manufacture of .these baflies it is notnecessary to make a half dozen or so different kinds of baflies withdifferent sized openings; the workman installing the furnace uses thesame kind of baiiles for all of the radiator sections and merely knocksout enough material at the opening 81' to enlarge the opening to theextent desired for any particular radiator section. The back of eachbafiie is formed with inclined marginal edges 85 arranged to fit oncomplementarily formed seats 86 in the radiator sections defining theedges of the outlet openings 81, whereby to insure at snug fit. A hollowboss 87, cast on the front of each baflie, provides a recess 88 fortheaccommodation of the end of the cleat '79, and the back wall of therecess 88 is made inclined at an acute .angle with reference to avertical, as indicated at 89, and the ends of the cleat 79 arecorrespondingly inclined, as indicated in dotted lines in Fig. 3, sothat the cleats '79 when entered in the recesses 88 and struck a lightblow, will serve to wedge the baiiies 80 properly into place on theirseats 86. Lugs 90 are cast in the radiator sections above the outletopenings 81' with sufl'icient room left between the openings andthe'lugs for the upper ends of the baflies to be entered therebetween,and horizontally projecting lugs 91 are provided below said outlets toserve as supports for thelower ends of the baflies. Thus, both bafliesof an opposed pair can be put in place and will not drop out before thecleat is inserted, which greatly facilitates the matter of installation.In the operation of the furnace, the baffles impose enough restrictionon the flow of the products of combustion through the intermediateradiator sections so that the flow is no faster through these sectionsthan through the sections at either end of the radiator unit. The inlets92 for all of the columns are sufiiciently large so that there is neverany danger of floating, because there is easy take-off of the productsof combustion.

It is believed the foregoing description conveys a clear understandingof all of the important objects and advantages of my invention. While Ihave made reference to various details of construction, it should beunderstood that the invention, for the most part, is not particularlylimited thereto, and many changes might be made without seriouslydeparting from or sacrificing advantages of my invention. For example,while I have shown a furnace, the casing of which encloses a singleradiator unit 12, it should be understoodthat I may connect two or moreradiator units in series on the same gas supply pipe 18 and. build asingle casing about the same with a single hood for the top thereof,that is, where a large building is to be heated and a single radiatorunit would not give suflicient heat. In such a multiple unit furnaceeach of the radiator units is suitcombustion manifold to the fluemanifold for discharge from the furnace, and a casing enclosing themanifolds and radiator columns and having a lower cold air inlet and anupper hot air outlet, the draft effect at the ends of the flue manifoldbeing lighter than at the middle of said-manifold,

and means for restricting the passage of products of combustion intosaid manifold from certain of the radiator columns disposed intermediatethe ends of said manifold whereby to cause all of said columns tofunction substantially the same.

2. In a furnace, the combination of an elongated fuel bumer, anelongated combustion manifold therefor, an elongated flue manifold abovethe latter, rows of spaced vertically disposed hollow radiator columnsestablishing communication between the two manifolds to conduct theproducts of combustion from the combustion manifold to .the fluemanifold for discharge from the furnace, and a casing enclosing the,manifolds and radiator columns and having' an inlet and outlet for theadmission and discharge of fluid to be heated, the draft effect at theends of the flue manifold being lighter than at the middle of saidmanifold, and means for restricting the passage of products ofcombustion into said manifold from certain of the radiator columnsdisposed intermediate the ends of said manifold whereby to cause all ofsaid columns to function substantially the same.

3. In' a hot air furnace, the combination of an elongated burner, aplurality of similar radiator sections each comprising an upper hollowhousing portion and a lower hollow housing portion, open fore and aft,and one or more hollow columns joining said housings, said sectionsbeing arranged to be placed side by side with the upper housings thereofin abutting communicating relation and the lower housings thereof inabutting communicating relation to form an elongated flue manifold withthe upper housings and an elongated combustion manifold with the lowerhousings, means for securing the radiator sections together, the saidburner being disposed within the combustion manifold and extendingsubstantially the full length thereof, whereby the products ofcombustion therefrom are distributed for passage upwardly through all ofsaid columns to the flue manifold for discharge from the furnace, a flueoutlet connection for said manifold, a clo sure member for one end ofthe combustion manifold, an open hollow inlet member at the other end ofsaid manifold, said members being secured to the opposite ends of themanifold and being formed whereby to serve as supports for the oppositeends of said radiator unit, anda casing enclosing said radiator unit andhaving a cold air inlet and a hot air outlet, one of said supports beingrigid and immovable, and the other of said supports being movable so asto allow for expansion and contraction of the radiator unit.

4. In a hot air furnace, the combination of an elongated burner, aplurality of similar radiator sections each comprising an upper hollowhousing portion and a lower hollow housing portion, open fore and aft,and one or more hollow columns joining said housings, said sectionsbeing arranged to be placed side by side with the upper housingstherofin abutting communicating relation and the lower housings thereof inabutting communicating relation to form an elongated flue manifold withthe upper housings and an elongated combustion manifold with the lowerhousings, means for securing the radiator sections together, the saidburner being disposed within the combustion manifold and extendingsubstantially the full length thereof, whereby the products ofcombustion therefrom are distributed for passage upwardly through all ofsaid columns to the flue manifold for dischargefrom the furnace, a flueoutlet connection for said manifold, a closure member for one end of thecombustion manifold, an open hollow. inlet member at the other end ofsaid manifold, said members being secured to the opposite ends of themanifold and being formed whereby to serve as supports for the oppositeends of said radiator unit, and a casing enclosing said radiator unitand having a cold air inlet and a hot air outlet, the front memberhaving rig-id supporting legs depending therefrom to provide a fixedfront support for the radiatoi' unit, and the member at the other end ofthe combustion manifold having a supporting leg pivotally connectedtherewith andarranged to rock 'to and fro when the radiator unit expandsand contracts. a

5. In a hot air furnace, the combination of an elongated burner, aplurality of similar radiator sections each comprising an upper hollowhousing portion and a lower hollow housing portion, open fore and aft,and one or more holl'owcolumns joining said housings, said sectionsbeing arranged to be placed side by side with the upper housings thereofin abutting communicating relation and the lower housings thereof inabutting communicating relation to form an elongated flue manifold withthe upper housings and an elongated combustion manifold with the lowerhousings, means for securing the radiator sections together, the saidburner being disposed within the combustion manifold and extendingsubstantially the full length thereof, whereby the products ofcombustion therefrom are distributed for passage upwardly through all ofsaid columns to the flue manifold for discharge from the furnace, a flueoutlet connection for said manifold, a. closure member for one endof thecombustion manifold, an open hollow inlet member at the other end ofsaid manifold, said members beingsecured to the opposite ends of themanifold and being formed whereby to serve as supports for the oppositeends of said radiator unit, and a casing enclosing said radiator unitand having a cold air inlet and a hot air outlet, the front memberhaving rigid supporting legs depending therefrom to provide a fixedfront supportfor the radlator unit, and the member at the other end ofthe combustion manifold having a supporting leg pivotally connectedtherewith and arranged to,

rock to and fro when the radiator unit expands and contracts, the saidstructure including floor engaging screws on the supporting legsarranged to be adjusted so as to level the radiator unit irrespective ofunevenness of the floor on which the furnace is mounted, the saidadjusting screws permitting rocking motion of the last mentionedsupporting leg.

6. In a hot air furnace, the combination of an elongated burner, aradiator unit comprising an elongated combustion manifold receiving saidburner, an elongated flue manifold, and spaced hollow columns extendingfrom the combustion manifold to the flue manifold for conducting theproducts of combustion from the former to the latter for discharge fromthe furnace, a rigid support for said radiator unit at one end of saidcombustion manifold, a support pivotally connected with the other end ofsaid manifold and adapted to oscillate relative to the floor to supportthe other end of the radiator unit so as to permit expansion andcontraction of said unit in operation, and a casing enclosing theradiator unit and having a lower cold air inlet and an upper hot airoutlet.

7. A structure as set forth in claim 6 including two laterally spacedadjusting screws on each of said supports for the purpose of permittingleveling of the radiator unit longitudinally and transverselyirrespective of unevenness of the'floor on which the same is mounted,the screws on the oscillating support permitting oscillation thereof.

8. In a hot air furnace, the combination of an elongated. burner, aradiator unit'comprising an elongated combustion manifold receiving saidburner, an.elongated flue manifold, and spaced hollow columns extendingfrom the combustion manifold to the flue manifold for conducting theproducts of combustion from the former to the latter for discharge fromthe furnace, means for supporting the radiator unit so that the frontend thereof is rigid and the other end thereof is movable asnecessitated for expansion and contraction of said unit in operation,and a narrow elongated casing for said unit having one end wall thereofsecured to the rigid end of said unit, there being an air inlet openinginto the combustion manifold at the rigid end thereof, and said casinghaving a lower cold air inlet and an upper hot air outlet.

9. A furnace, as set forth in claim 8, wherein the walls of said casingare insulated to minimize heat dissipation from the radiator unittherethrough, said casing including an insulating air chamber at thatend thereof to which the rigid end of the radiator unit is secured, thesaid end wall of the casing to which said unit is secured constitutingthe inner wall of said chamber, said chamber providing a space thereinfor the valves and other controls of the radiator unit, and a doorforming the outer wall of said chamber and arranged when opened toafford access to the valves and to the radiator unit.

10. In a hot air furnace, having a radiator unit comprising a combustionmanifold, a flue mani-' removably disposed in said casing between andsupported by two laterally spaced rows of radiator columns in a positionabove the combustion manifold and arranged to contain water for thehumidification of the air passed through the casing, said pan beingentered endwise through the end of the radiator unit betweenthe.laterally spaced rows of columns.

11. A furnace as set forth in claim 10, wherein said casing has onewallthereof to which the radiator unit is attached, provided with an airinlet opening for the burner, said humidifier pan being removablyinserted through another opening provided in the same wall.

12. A furnace as set forth in claim 10, wherein the columns havelongitudinally extending flangesfor radiating heat therefrom, the saidflanges on the inner opposed edges of the columns being provided withaligned notches, and said pan having longitudinally extending outwardlyprojecting flanges on opposite sides thereof entered in said notches forthe support of the pan on the columns.

13. In a furnace comprising a combustion manifold, a flue manifold, anda plurality of hollow columns reaching from one manifold to the otherand communicating through inlet openings with the combustion manifoldand through outlet openings with the flue manifold, the inlet openingsbeing all of substantially the same size, and the outlet openings beingall of substantially the same size, bafiles for the one set of openingsfor imposing different restrictions on the flow of products ofcombustion through the different columns according to the draft effectfor the different columns.

14. In a furnace comprising acombustion manifold, a flue manifold, and aplurality of hollow columns reachin from one manifold to the other andcommuni ating through inlet openings with the combustion manifold andthrough outlet openings with the flue manifold, the inlet openings beingall of substantially the same size, and the outletopenings being all ofsubstantially the same size, baffles for the outlet openings forimposing different restrictions on the flow of products of combustionthrough the different columns according to the draft effect for thedifferent columns.

15. In a furnfie comprising a combustion manifold, a flue manifold, anda plurality of holl'. )V columns reaching from one manifold to the otherand communicating through inlet openings with the combustion manifoldand throu h outlet openings with the flue manifold, the inlet openingsbeing all of substantially the same size; and the outlet openings beingall of substantially the same size, a plurality of separate bafileplates having difierent sized openings provided therein, said bafiiesbeing placed in the outlet openings to impose different restrictions onthe flow of products of combustion through the different columnsaccording to the draft eflect at each outlet opening.

16. In a furnace comprising a combustion manifold, a flue manifold, anda plurality of hollow columns reaching from one manifold to the otherand communicating through inlet openings with the combustion manifoldand through outlet openings with the flue manifold, the inlet openingsbeing all of substantially the same size, and the outlet openings beingall of substantially the same size, a plurality of separate baflieplates all of the same construction entered in the outlet openings, saidbaflie plates all having certain portions thereof at a predeterminedelevation arranged to have openings formed therein, thedifferent bafileshaving different sized openings made therein to impose differentrestrictions on the flow of the products of combustion through thedifferent columns according to the draft effect at the different outletopenings.

17. In a furnace comprising a plurality of radiator sections disposed ina row providing an elongated combustion manifold, an elongated fluemanifold and two rows of hollow columns joining the manifolds, the saidcolumns being in communication with the combustion manifold throughinlet openings, all of substantially the same size, and being incommunication with opposite sides of the flue manifold through two rowsof opposed outlet openings, all of substantially the same size, baflieson the flue manifold covering the two rows of outlet openings, thebaflies having different sized openings therethrough to impose differentrestrictions on the flow of products of combustion through the differentcolumns according to the draft effect at the different outlet openings,and ineans disposed between the two rows of bafiles for holding the samein place.

18. A furnace as set forth in claim 1'7, wherein each pair of baflleshas a separate cleat reaching therebetween for holding the two bafllesin place at opposite ends of the cleat.

19. A furnace as set forth in claim 17, wherein the baffles aresubstantially vertically disposed, there being lugs at the upper endsthereof provided in the flue manifold in spaced relation to the outletopenings for receiving the upper ends of the baflles therebetween, andledges provided in the flue manifold below said outlet openings whereonthe lower ends of the baffles are arranged to be supported, the ledgesand lugs cooperating to keep the baffles from dropping out of placebefore they are secured.

20. In a furnace comprising a plurality of radiator sections providing acombustion manifold, a flue manifold and hollow columns joining themanifolds, the said columns being in communication with the combustionmanifold through inlet openings all of substantially the same size, andbeing in communication with opposite sides of the flue manifold throughtwo rows of opposed outlet openings, all of substantially the same size,the said inlets being of relatively enlarged size for easy take-off ofthe products of combustion from the combustion manifold, and thepassages in said columns being diminished in size at the opposite endsso as to provide relatively smaller outlets so as to avoid too rapidflow of the products through the columns. 21. In a furnace comprising aplurality of radiator sectionsproviding a combustion mani fold, a fluemanifold and hollow columns joining the manifolds, the said columnsbeing in communication with the combustion manifold through inletopenings, all of substantially the same size, and being in communicationwith opposite sides of the flue manifold through two rows of opposedoutlet openings, all of substantially the same size, the said inletsbeing of relatively enlarged size for easy take-off of the products ofcombustion from the combustion manifold, and the passages in saidcolumns being diminished in size at the opposite ends so as to providerelatively smaller outlets so as to avoid too rapid flow of the productsthrough the columns, and baffle means for the outlet openings forimposing different restrictions on the flow of the products ofcombustion through the different columns according to thedraft effectfor the different columns.

22. In a furnace comprising a plurality of radiator sections providingan elongated combustion manifold, an elongated flue manifold above andsubstantially parallel with the combustion manifold, and pairs of hollowcolumns, one pair on each radiator section, joining the manifolds, thesaid columns having each pair branching ofi the opposite sides of thetop of the combustion manifold, the inlet openings into the lower endsof said columnsbeing all of substantially the same size, the saidcolumns having each pair communicating with opposite sides of the fluemanifold through opposed outlet openings, all of sub stantially the samesize, the said inlets being of relatively enlarged size for easytake-off of the products of combustion from i the combustion manifold,the products being divided in each radiator section between the pair ofcolumns of said section, and the passages in said columns beingdiminished in size at the opposite ends so as to provide relativelysmaller outlets so as to avoid too rapid flow of the products throughthe columns, and means for restricting the passage of the products ofcombustion into said'flue manifold from certain of the radiator columnsdisposed intermediate the ends of said manifold whereby to cause all ofsaid columns to function substantially the same. i

23. In a furnace, the combination of a radiator unit comprising anelongated combustion manifold, an elongated flue manifold, and spacedhollow columns extending from the combustion manifold to the fluemanifold for conducting the products of combustion from the former tothe latter for discharge from thefumace, a rigid support for saidradiator unit at one end of said combustion manifold, a supportpivotally connected with the other end of said manifold and adapted tooscillate relative to the floor to support the other end of the radiatorunit so as to permit expansion and contraction of said unit inoperation, and a casing enclosing the radiator unit and having a coldair inlet and a hot air outlet properly disposed with respect to theradiator unit.

24. In a furnace, the combination of a radiator unit comprising anelongated combustion manifold, an elongated flue manifold, and spacedhollow columns extending from the combustion manifold to the fluemanifold for conducting the products of combustion from the former tothe latter for discharge from the furnace, a rigid support for saidradiator unit at one end of said comsaid manifold adapted to oscillaterelative to the tion, and a casing enclosing the radiator unit andhaving a cold air inlet and a hot air outlet properly disposed withrespect to the radiator unit.

25. A radiator section for a gasheater or the like comprising acombustion chamber portion, a flue chamber portion having its centervertically above the combustion chamber portion, and a verticallydisposed heat radiating conduit connecting the top of the combustionchamber portion with the side of the flue chamber portion, said conduitbeing of flattened cross-section in a plane transverse with reference tothe axes of the two chambers whereby to stratify the products ofcombustion into a thin stream to facilitate dissipation of the heattherefrom, the said conduit being furthermore longitudinally corrugatedso as to divide the same into a plurality of more or less separatelongitudinal passages and thus cause the thin stream of products to besplit up further into a multiplicity of separate streams from which theheat is dissipated through the walls of the conduit enclosing thestreams on substantially all sides for efficient dissipation of the heattherefrom, 'the longitudinal corrugations affording longitudinalchannels on the outside of the conduit arranged to conduct streams ofair, with minimum obstruction to flow, in

straight paths lengthwise of the conduit to ab-' stract heat therefrom.

26. In a furnace, the combination of a radiator unit comprising anelongated combustion manifold, an-elongated flue manifold, and spacedhollow columns extending from the combustion manifold to the fluemanifold for conducting the products of combustion from the former tothe latter for discharge from the furnace, means for supporting theradiator unit so that the front end thereof is rigid and the other endthereof is movable as necessitated for expansion and contraction of saidunit in operation, and a casing for enclosing said unit having one endwall thereof made rigid with the rigid end of the unit, the other wallsbeing spaced from the rest of the unit, the casing having a cold airinlet and a hot air outlet properly disposed with reference to saidunit,- the said casing being extended beyond the front end of, theradiator unit to provide a small insulating chamber, and a front closurewall for said chamber affording access thereto.

27. In a hot air furnace, the combination of a radiator unit having acombustion manifold, a burner received in said manifold, a casing forair to be heated enclosing the radiator unit from all sides, the frontwall of said casing having an opening provided therein for directlyadmitting air to the combustion manifold to support combustion therein,the burner also having a fuel delivery pipe extending thereto throughsaid opening, the walls'of said casing with the exception of said frontwall being suitably insulated to minimize heat dissipation from theradiator unit, an insu- 28. A structure as set forth in claim 27,wherein the door has one or more air vents provided therein opposite theopening in the inner wall of said chamber for admitting air to supportcombustion in the combustion manifold;

29. A structure as set forth in claim 27, wherein the radiator unitcomprises a flue manifold above the combustion manifold having anormally closed opening provided therein immediately behind the innerwall of the insulating air chamber, said in ner wall having an openingprovided therein through which access is afforded to the flue manifold,the structure including a removable closure for the opening in the fluemanifold and a re- 'movab1e closure for the opening in said inner wall.

30. A structure as set forth in claim 27, wherein the radiator unitcomprises a plurality of spaced rows of hollow columns extendingupwardly from the combustion manifold to conduct products of combustiontherefrom for discharge from the furnace and arranged to radiate theheat therefrom, and wherein the inner wall of the insulating air chamberhas an opening provided therein, the structure including a humidifierpan removably entered in said opening and disposed between the laterallyspaced rows of columns of the radiator.

31. In a gas fired hot air furnace comprising a casing of elongated formhaving a lower cold air inlet and an upper warm air outlet, a gas heatedradiator unit of elongated form disposed lengthwise in said casing, thesame comprising an elongated lower burner manifold, an elongated upperflue manifold, the manifolds being substantially centrally disposed withrespect to the casing with the flue manifold in a vertical plane abovethe burner manifold, and radiator columns extending upwardly from theburner manifold to the flue manifold to conduct products, of combustionto the latter, said columns being disposed substantially wholly toeither side of the plane of the manifolds in the direct path of airrising through said casing from the inlet to the outlet, whereby totransfer heat thereto, the said columns being of flattened form wherebyto stratify the products of combustion into thin streams in the passagethereof through said columns to facilitate dissipation of the heattherefrom, and said columns being furthermore conformed in cross-sectiontoprovide a plurality of longitudinal passages therein to further dividethe products into a multiplicity of streams in flowing the columns arefurthermore conformed in crosssection so as to provide on the outsidethereof a plurality of separate longitudinal channels between thelongitudinal passages in the inside for the flow of air therein alongthe outside of the columns in heat transferring relation to the productsof combustion conducted through the internal longitudinal passages.

33. In a furnace comprising a casing of elongated form having a lowercold air inlet and an upper warm air outlet, a radiator unit ofelongated form disposed lengthwise in said casing, the same comprisingan elongated lower combustion manifold, an elongated upper fluemanifold, the manifolds being substantially' centrally disposed withrespect to the casing with the flue manifold in a vertical plane abovethe combustion manifold, and radiato'rcolumns extending upwardly fromthe combustion manifold to the flue manifold to conduct products ofcombustion to the latter, said columns being disposed. submsaersstantially wholly to either side of the plane of the manifolds in thedirect path of air rising through said casing from the inlet to theoutlet, whereby to transfer heat thereto, the said columns being offlattened form whereby to stratify the products of combustion into thinstreams in the passage thereof through said columns to facilitatedissipation of the heat therefrom, and said columns being furthermoreconformed in cross-section to provide a plurality of longitudinalpassages therein to further divide the products into a multiplicity ofstreams in flowing from the combustion manifold to the flue manifold,whereby to still further facilitate heat dissipation.

34. A furnace as set forth in claim 33, wherein the columns arefurthermore conformed in crosssection so as to provide on the outsidethereof a plurality of separate longitudinal channels between thelongitudinal passages in the inside for the flow of air. therein alongthe outside of the columns in heat transferring relation to the productsof combustion conducted through the internal longitudinal passages.

35. A radiator section for a gas heater or the like comprising acombustion chamber portion, a flue chamber portion having its centervertically above the combustion chamber portion, and a verticallydisposed heat radiating conduit connecting the top of the combustionchamber portion with the side of the flue chamber portion, said conduitbeing of flattened cross-section in a plane transverse with reference tothe axes of the two chambers whereby to startify the products ofcombustion into a thin stream to facilitate dissipation of the heattherefrom, the said conduit being furthermore longitudinally corrugatedso as to divide the same into a plurality of more or less separatelongitudinal passages and thus cause the thin stream of products to besplit up further into a multiplicity of separate streams from which theheat is dissipated through the walls of the conduit enclosing thestreams on substantially all sides for eflicient dissipation of the heattherefrom.

36. In a furnace, the combination of a radiator unit. comprising anelongated combustion manifold, an elongated flue manifold, and spacedhollow columns extending from the combustion manifold to the fluemanifold to conduct products of combustion from the former to the latterfor discharge from the furnace, a rigid support for said radiator unitat-oneend of one of said manifolds, a support pivotally connected withthe other end of said manifold to oscillate relative to the floor in theexpansion and contraction of said unit in operation, and a casingenclosing the unit and having a cold air inlet and a hot air outlet.

3'7. In a furnace, the combination of an elongated radiator unit, arigid support for the radiator unit at one end thereof, a supportpivotally connected with the other end of said unit and adapted tooscillate relative to the floor in the expansion and contraction of saidunit in opera-- tion, and a casing enclosing the unit and having a coldair inlet and a hot air outlet.

38. In a furnace comprising a casing having a cold air inlet and a warmair outlet, a radiator unit disposed in said casing between the inletand outlet, the same comprising a combustion manifold and a fluemanifold in spaced relation to one another, and hollow radiator membersextending from the combustion manifold to the flue manifold to conductproducts of combustion from the former to the latter, and in so doingtransfer heat from the surface of the members to the air circulatingthroughthe casing from the inlet to the.outlet, said hollow radiatormembers being of flattened form so that the thickness of cross-sectionis small in relation to the width whereby to stratify the products intocorrespond.- ingly thin streams'in the passage thereof through saidmembers and facilitate dissipation of heat therefrom, and said hollowradiator members being furthermore conformed in cross-section to providea plurality of laterally spaced longitudinal passages therein havingrestricted communication substantially their full length in whichpassages the thin'streams of products are sub-divided into amultiplicity of laterally intercommunicating streams in flowingtherethrough, whereby further to facilitate heat dissipation, the endsof said hollow radiator members being formed so that all of saidlongitudinal passages communicate at their ends directly with thecombustion manifoldand flue manifold.

39. A furnace as set forth in claim 38 wherein the hollow radiatormembers are furthermore conformed in cross-section so as to provide onthe outside thereof a plurality of separate longi tudinal channelsbetween the longitudinal passages in the inside, whereby to permit theflow of air along the channels on the outside of the members in intimateheat transferring relation to the products of combustion conductedthrough the internal longitudinal passages.

40. A unit for a sectional furnace comprising a combustion chamberportion, a flue chamber portion in spaced relation to the latter, and ahollow radiator member connecting said portions to conduct products ofcombustion therebetween, said hollow radiating member being of flattenedform so that the thickness of cross-section is small in relation to thewidth, whereby to stratify the products into correspondingly thinstreams in the passage thereof through said member and facilitate.dissipation of heat therefrom, and said hollow radiating member beingfurthermore conformed in cross-section to provide a plurality oflaterally spaced longitudinal passages therein having restrictedcommunication substantially their full length in which the products aresubdivided into a multiplicity of laterally intercommunicating streamsin flowing therethrough, whereby further to facilitate heat dissipation,the ends of said hollow radiating member being formed so that all ofsaid longitudinal passages communicate at their ends directly with thecombustion chamber portion and flue chamber portion.

STA NLEY H. HOBSON.

